Respiratory protection mask for a compressed air breathing apparatus

ABSTRACT

The invention relates to a respiratory protection mask for a compressed air breathing apparatus comprising a pulmonary machine ( 2 ) which is controlled by a control membrane ( 4 ) when the wearer of the mask breathes in. According to the invention, the air outlet ( 8 ) of the expiratory valve ( 7 ) and the control membrane ( 4 ) are covered by a common cover ( 9 ), forming a rinsing area ( 10 ) on the outside of the control membrane through which homogeneously temperate, clean rinsing air flows from the air outlet ( 8 ) to the air discharge openings ( 11 ) in the cover, thereby ensuring high functionality and high service life of the membrane-controlled pulmonary machine despite extreme environmental conditions.

This invention relates to a respirator mask for a compressed airbreathing apparatus with a lung machine controlled by a control membraneand an expiratory valve with an air outlet.

Respirator masks, when combined with a compressed air respirator, aretypically operated with a lung machine that is connected to thefacepiece by a screwed or plug-in connection. The air supply from apressure reducer via a medium-pressure line is controlled by a controlmembrane operated by the mask wearer's inhaling that mechanically actson a control valve which in turn releases the medium-pressure line asrequired. The thin membrane made of an elastic material is of coursehighly sensitive to environmental conditions involving extremetemperatures and aggressive media. The functioning of the membrane maybe impaired, for example, by reduced elasticity in low temperatureswhich adversely affects resistance to breathing and sensitivity, or ifthe membrane material is penetrated, destroyed, or severely mechanicallydamaged by aggressive gases such as hydrogen sulfide or phosgene.

It is therefore the problem of the invention to design a respirator maskof the type mentioned at the outset in such a way that the functioningof the control membrane is not impaired by temperatures and aggressivemedia and thus a long service life is ensured.

This problem is solved according to the invention by a respirator maskcomprising the characteristics described in claim 1. The dependentclaims disclose further advantageous improvements of the invention.

The general concept of the invention is a common lid that covers the airoutlet of the expiratory valve and the control valve and that comprisesair discharge openings on the opposite side, i.e. the side facing awayfrom the air outlet. Thus a purging space or duct is created in whichthe mask wearer's clean expiratory air flows at a homogeneoustemperature from the air outlet across the surface of the controlmembrane and washes away the aggressive gases while keeping the membraneat an equal temperature, or cools or heats it depending on the outsidetemperature. This ensures undisturbed functionality and a long servicelife of the control membrane.

An embodiment of the invention will be explained in greater detail belowwith reference to the only figure showing a partial sectional view of arespiratory mask with a lung machine attached to it.

The facepiece 1 is equipped with a lung machine 2 for supplyingrespiratory air to the wearer of the mask from a compressed airreservoir via a pressure reducer and a medium-pressure line 3. Airsupply is controlled according to the rhythm of breathing by aninhale-operated control membrane 4 that is connected via a linkage to acontrol valve (not shown) that opens the medium-pressure line 3 when thewearer inhales. Arrows A, B, and C show the path of the inhalation airalong the dashed line from the medium-pressure line 3 via the chamber 5and the air inlet 6 of the lung machine and along the visor panels 12 tothe wearer of the mask while the used air is exhaled in the direction ofarrows D, E, and F through the expiratory valve 7. As can be seen in thefigure, the air the wearer of the mask exhales does not immediately flowoutside but through an air outlet 8 into the purging space 10 defined bythe lid 9 above the control membrane 4. This means that clean andhomogeneously tempered purging air, i.e. the exhalation air of thewearer of the mask, is conducted across the surface of the controlmembrane 4 with each exhalation cycle. This keeps the control membrane 4at an equal temperature regardless of the outside temperature so thatits functioning is neither limited by high nor by low outsidetemperatures. The control membrane 4 becomes neither too rigid nor toosoft but keeps its predefined mechanical properties. Breathingconditions remain optimal for the wearer of the mask even under extremeconditions. Furthermore, aggressive toxic gases such as hydrogen sulfideor phosgene that can diffuse the thin control membrane relatively fastand harm the wearer of the equipment are continuously washed away fromthe control membrane 4 thereby eliminating the risk of impairment andensuring a long service life and purity of the inhalation air. Theexhaled fair (purging air) is discharged through air discharge openings11 in the lid 9.

List of Reference Symbols

-   1 Facepiece-   2 Lung machine-   3 Medium-pressure line-   4 Control membrane-   5 Chamber-   6 Air inlet-   7 Expiratory valve-   8 Air outlet-   9 Lid-   10 Purging space-   11 Air discharge openings-   12 Visor panels-   Arrows A-B-C path of the inhaled air-   Arrows D-E-F path of the exhaled air

1. A respirator mask for a compressed air breathing apparatus with alung machine controlled by a control membrane and an expiratory valvewith an air outlet, wherein the air outlet of the expiratory valve andthe control membrane of the lung machine are covered at a spacing by acommon lid comprising air discharge openings on the side of the lid thatfaces away from the air outlet and forming a purging space above thecontrol membrane.
 2. The respirator mask according to claim 1,characterized in that the lid for forming a duct runs at an equal smalldistance above the control membrane to separate it from the ambientatmosphere.
 3. The respirator mask according to claim 1, characterizedin that the lid is an integral part of the lung machine or therespirator mask, respectively, or is separately attached to any of thelung machine or respirator mask.
 4. The respirator mask according toclaim 2, characterized in that the lid is an integral part of the lungmachine or the respirator mask, respectively, or is separately attachedto any of the lung machine or respirator mask.